Friction stir joining device and friction stir joining method

Abstract

To provide a friction stir joining device that can obtain a desired joint strength without requiring screw fastening and so on even if an area of a joined component is relatively large in friction stir joining of a laminate member in which a plurality of joined components are laminated in a thickness direction.SOLUTION: A friction stir joining device forms a laminate by friction stir joining a laminated interface of a laminate member in which a first component and a second component, which respectively have a prescribed thickness, are laminated in a thickness direction in such a manner that the first component is arranged on a lower side and the second component is arranged on an upper side. The joining device forms the laminate by setting a virtual XYZ space at a reference height position that indicates a prescribed height position in an upper part direction of a placement table on which the laminate is placed, advancing a joining tool at a prescribed advance speed while rotating the same at a prescribed rotational speed along one or a plurality of joining lines set by (X, Y, Z) coordinates in the XYZ space, and friction stir joining the laminate interface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to the configuration and control of a friction stir welding apparatus that joins workpieces together by friction stir welding, and in particular to a technique that is effective when applied to joining a laminated member in which a plurality of workpieces are stacked in the thickness direction. [Background technology]

[0002] Friction stir welding (FSW) involves softening the materials to be joined using frictional heat generated by rotating a cylindrical joining tool, and then stirring the softened materials to join them together. Because no materials other than the materials themselves are used, FSW has high fatigue strength and, because the materials do not melt, allows for joining with little welding deformation (distortion). It is expected to be applied in a wide range of fields, such as aircraft and automobile bodies.

[0003] Friction stir welding of plate-shaped metal members using a friction stir welding device can be performed in two ways: by arranging the side of a first member and the side of a second member adjacent to each other and joining the adjacent parts, and by friction stir welding the lamination interface of a laminated member in which the first member and the second member are stacked in the thickness direction.

[0004] Laminates formed by stacking materials in the thickness direction and friction stir welding the lamination interfaces are expected to be in demand as parts manufactured by metal additive manufacturing in the aerospace, automotive, and building materials fields. Metal additive manufacturing is characterized by its ability to realize complex shapes and to realize the manufacturing of aluminum alloys, which are difficult to achieve by laser sintering.

[0005] Background art in this technical field includes, for example, technology such as that disclosed in Patent Document 1. Patent Document 1 discloses "a friction stir welding method for joining two or more stacked metal plates of the same or different types by a friction stir process, in which, before the friction stir process, holes for friction stir welding are formed that penetrate all layers of the stacked metal plates, and in the friction stir process, friction heat is generated between the inner surface of the through hole and an insertion pin of a friction stir welding tool that is inserted into the through hole, thereby frictionally stirring the stacked metal plates from the inner surface side of the through hole." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-173163 Summary of the Invention [Problem to be solved by the invention]

[0007] The friction stir welding method described in Patent Document 1 is effective in cases where small-area laminated metals are spot-joined, or where through-holes are screwed after friction stir welding.

[0008] However, in cases where large-area components are not fastened with screws after joining, the desired joint strength cannot be obtained, and there is room for improvement.

[0009] Therefore, an object of the present invention is to provide a friction stir welding apparatus and a friction stir welding method using the same that can obtain the desired joint strength in friction stir welding of laminated members in which multiple workpieces are stacked in the thickness direction, even when the workpieces have a relatively large area, without requiring screw fastening or the like after friction stir welding. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the present invention provides a friction stir welding device that forms a laminate by friction stir welding the lamination interface of laminated members that are stacked in the thickness direction, with a first member and a second member, each of which is made of plate-shaped metal and has a predetermined thickness, with the first member placed on the lower side and the second member placed on the upper side, and characterized in that a virtual XYZ space is set at a reference height position that indicates a predetermined height position above a mounting table on which the laminated members are placed, and a welding tool is rotated at a predetermined rotational speed and advanced at a predetermined advancement speed along one or more welding lines that are set by the (X, Y, Z) coordinates in the XYZ space, thereby friction stir welding the lamination interface, thereby forming the laminate.

[0011] The present invention also provides a friction stir welding method for forming a laminate by friction stir welding the lamination interfaces of laminated members that are stacked in the thickness direction, with a first member and a second member, each of which is made of plate-shaped metal and has a predetermined thickness, with the first member placed on the lower side and the second member placed on the upper side, characterized in that the method comprises the steps of: (a) setting a virtual XYZ space at a reference height position that indicates a predetermined height position above a mounting table on which the laminated members are placed; (b) setting one or more welding lines that are set by (X, Y, Z) coordinates in the XYZ space; and (c) rotating a welding tool at a predetermined rotational speed while advancing it at a predetermined advancing speed along the welding lines to friction stir weld the lamination interfaces, thereby forming the laminate. [Effects of the Invention]

[0012] According to the present invention, it is possible to realize a friction stir welding apparatus and a friction stir welding method using the same that can obtain the desired joint strength in friction stir welding of a laminated member in which multiple workpieces are stacked in the thickness direction, even when the workpieces have a relatively large area, without requiring screw fastening or the like after friction stir welding.

[0013] This makes it possible to form a laminate with high bonding strength.

[0014] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B are diagrams showing a laminated member and a laminated body according to Example 1 of the present invention. [Figure 2] FIG. 2 is a diagram showing an XYZ space according to the first embodiment of the present invention. [Figure 3A] FIG. 2 is a diagram showing an XYZ space according to the first embodiment of the present invention. [Figure 3B] FIG. 2 is a diagram showing an XYZ space according to the first embodiment of the present invention. [Figure 4A] FIG. 10 is a diagram showing the Z coordinate of the insertion depth of a joining tool into a laminated member. [Figure 4B] FIG. 10 is a diagram showing the insertion direction of a joining tool into laminated members. [Figure 5] FIG. 10 is a diagram showing a joining line set on the XY plane at an insertion depth Z1. [Figure 6] FIG. 10 is a diagram showing a joining line set on the XY plane at an insertion depth Z1. [Figure 7] 1 is a flowchart showing a friction stir welding method according to a first embodiment of the present invention. [Figure 8] 10A and 10B are diagrams illustrating a process for forming a stack of a desired number of layers. [Figure 9A] FIG. 10 is a diagram showing a process for forming a three-layer laminate according to Example 2 of the present invention. [Figure 9B] FIG. 10 is a diagram showing a process for forming a three-layer laminate according to Example 2 of the present invention. [Figure 9C] FIG. 10 is a diagram showing a process for forming a three-layer laminate according to Example 2 of the present invention. [Figure 10] 1 is a diagram showing an overview of a friction stir welding apparatus according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are designated by the same reference numerals, and detailed description of overlapping parts will be omitted. [Example]

[0017] First, the configuration and control of a friction stir welding apparatus according to the present invention will be described with reference to Fig. 10. Fig. 10 is a diagram showing an overview of the entire friction stir welding apparatus according to this embodiment.

[0018] As shown in FIG. 10 , the friction stir welding apparatus 1 of this embodiment is mainly composed of an apparatus main body 2, a spindle support unit 4 connected to the apparatus main body 2 via a Z-axis up-down movement drive mechanism unit 3, a spindle holder 15 and a spindle 16 held by the spindle support unit 4, a welding tool holder 5 held by the spindle holder 15 and the spindle 16, and a welding tool 6 held by the welding tool holder 5.

[0019] As shown in Figure 10, the Z-axis up-down movement drive mechanism 3 uses, for example, a ball screw, a linear guide, etc., and drives the main shaft support part 4 in the Z-axis direction (up-down direction) relative to the device main body 2 by a Z-axis drive motor 17.

[0020] The welding tool 6 is composed of a shoulder portion 7 and a probe portion (welding pin) 8, and is connected (directly connected in FIG. 10) to a spindle motor 14. The spindle motor 14 rotates the welding tool 6 in a predetermined direction.

[0021] The device main body 2 supports a spindle support part 4 via a Z-axis vertical movement drive mechanism part 3, and a control part (control device) 11 mounted on (attached to) the device main body 2 sends a drive signal to a spindle motor 14 to rotate the welding tool 6 and move it along the welding line. In other words, the device main body 2 holds the spindle support part 4, the spindle holder 15, the spindle 16, and the welding tool holder 5, and rotates the welding tool 6 while moving it in the X-axis and Z-axis directions in Figure 10.

[0022] When the Z-axis drive motor 17 is driven, the spindle holder 15 moves up and down in conjunction with the Z-axis vertical movement drive mechanism 3, which moves up and down in response to the Z-axis drive motor 17's movement. The spindle holder 15 is equipped with a spindle 16 and a spindle motor 14 that applies a rotational force to the spindle 16. A welding tool holder 5 is attached to the tip of the spindle 16, and a welding tool 6 is attached to the tip of the welding tool holder 5. When the spindle motor 14 is rotated, the welding tool 6 rotates via the spindle 16 at the same rotational speed as the spindle motor 14.

[0023] While rotating the welding tool 6 at a predetermined rotation speed, the shoulder portion 7 and probe portion 8 are pressed against the welding line on the surfaces of the workpieces 9 (9a, 9b) placed on the mounting table 10, generating frictional heat to soften the workpieces 9, and the shoulder portion 7 and probe portion 8 are inserted into the workpieces 9 by the required amount. By maintaining this rotation speed, plastic flow occurs and the inserted portion is stirred. By withdrawing or moving the welding tool 6, the stirred portion (welding portion) is cooled and the workpieces 9 are welded.

[0024] 10 shows a configuration in which the joining tool holder 5 and the joining tool 6 are connected to (held by) the apparatus main body 2 via the spindle holder 15, the spindle 16, the spindle support unit 4, and the Z-axis vertical movement drive mechanism unit 3; however, the present invention is not limited to this configuration. For example, the scope of this embodiment also includes a configuration in which the joining tool holder 5 and the joining tool 6 are connected to (held by) the apparatus main body 2 only via the Z-axis vertical movement drive mechanism unit 3, a configuration in which the joining tool holder 5 and the joining tool 6 are connected to (held by) the apparatus main body 2 via other movable means, a configuration in which a C-frame is further provided between the joining tool holder 5 and the apparatus main body 2 in addition to the configuration of FIG. 10, and a configuration in which the joining tool holder 5 and the joining tool 6 are connected to (held by) the apparatus main body 2 having an industrial robot (multi-axis robot arm).

[0025] When an industrial robot is used as the device main body 2, a spindle holder 15 is connected to the tip of the arm of the industrial robot, and the movement of the joining tool 6 in the Z-axis direction and horizontal direction is performed by driving the arm of the industrial robot.

[0026] Furthermore, the joining tool may be one in which the shoulder portion 7 and the probe portion (joining pin) 8 are the same (that is, it does not have a probe and has only a shoulder), and the shoulder portion 7 may have a structure in which it does not rotate.

[0027] A control unit (control device) 11 that controls the operation of the friction stir welding apparatus 1 is installed (attached) to the apparatus main body 2. The control unit (control device) 11 is equipped with a storage unit (not shown) that stores welding parameters (FSW welding conditions) such as a welding condition signal that determines the welding conditions used by the welding tool 6 and a holding position determination signal that determines the holding position (insertion amount of the joining pin 8) in the vertical direction (Z direction) of the welding tool 6 using the Z-axis up-down movement drive mechanism unit 3. The control unit 11 may be configured as a control device separately from the apparatus main body 2.

[0028] The device main body 2 is also provided with an X-axis front-rear drive mechanism 12 that can be driven in the X-axis direction, and the joining tool holder 5 and the joining tool 6 can be moved in the X-axis direction (joining direction) by moving the upper part of the device main body 2 along the rails of a linear guide provided in the X-axis direction using an X-axis front-rear drive motor 13.

[0029] Next, a method for controlling the friction stir welding apparatus 1 of this embodiment will be described with reference to FIGS.

[0030] FIG. 1 is a diagram showing a laminated member 9, which is an object to be joined (member to be joined) in this example, and a laminated body 19 after joining.

[0031] The laminate 19 of this embodiment is a structure formed by using a first member (member to be joined 9a), which is a plate-shaped metal member having a predetermined thickness, and a second member (member to be joined 9b), which is also a plate-shaped metal member having a predetermined thickness, with the first member (member to be joined 9a) positioned on the bottom and the second member (member to be joined 9b) positioned on the top, and stacking them together, and friction stir welding the lamination interface 18 of the laminated member 9 along a welding line set at the lamination interface 18.

[0032] The thickness and area of ​​the first member (members to be joined 9a) and the second member (members to be joined 9b) may be the same or different. These specifications are determined depending on the application of the laminate 19 formed by friction stir welding.

[0033] The number of bonding lines set at the lamination interface 18 may be set according to the bonding strength required for the intended use of the laminate 19 to be formed. Setting one bonding line shortens the processing time but provides weak bonding strength. Setting five bonding lines lengthens the processing time but provides strong bonding strength. In other words, the bonding strength of the laminate 19 to be formed can be adjusted by changing the number of bonding lines set.

[0034] FIG. 2 shows a first diagram illustrating the XYZ space in this embodiment, and FIGS. 3A and 3B show second and third diagrams illustrating the XYZ space in this embodiment.

[0035] In the present invention, the joining line is set as follows.

[0036] First, a predetermined position above the mounting table 10 on which the workpieces to be welded are placed is set as a reference height position. Next, a virtual XYZ space is set at the reference height position. Then, in the XYZ space, a weld line is set as a collection of line segments connecting the (X, Y, Z) coordinates of the friction stir welding starting end, which indicates the position where friction stir welding starts, the (X, Y, Z) coordinates of the friction stir welding ending end, which indicates the position where friction stir welding ends, and the (X, Y, Z) coordinates of an intermediate point set at an intermediate position between the friction stir welding starting end and the friction stir welding ending end.

[0037] The tip of the joining tool 6 is inserted into the (X, Y, Z) coordinates of the starting end of the friction stir welding, and the tip of the joining tool 6 is advanced via the (X, Y, Z) coordinates of the midpoint to the (X, Y, Z) coordinates of the end of the friction stir welding, thereby friction stir welding the lamination interface 18 of the laminated member 9.

[0038] The intermediate points are set as needed. For example, if the joining line is set as a straight line connecting the starting end of the friction stir welding and the ending end of the friction stir welding, the number of intermediate points is zero. However, if the joining line is set as a complex shape that is close to a curve, multiple intermediate points must be set.

[0039] Furthermore, the number of intermediate points and the number of welding lines can be set to optimal values ​​according to the welding strength required for the operation of the laminate 19 to be formed by test welding the laminated member 9 prior to actually operating the friction stir welding apparatus 1.

[0040] This will be explained in detail below.

[0041] At the reference height position, a rectangular area that is the horizontal movable range of the welding tool 6 is set as a reference area. In the reference area, a predetermined position is set as the origin of the XYZ space represented by coordinates (X0, Y0, Z0).

[0042] A line segment connecting the origin (X0, Y0, Z0) and a predetermined position parallel to one side of the reference area and moving away from the device body 2 of the friction stir welding device 1 is set as the X axis.

[0043] A line segment that connects the origin (X0, Y0, Z0) and a predetermined position that is perpendicular to the X axis, parallel to one side of the reference area, and moves away from the origin is set as the Y axis.

[0044] A line segment that starts from the origin (X0, Y0, Z0) and extends vertically downward to the surface of the mounting table 10 is set as the Z axis.

[0045] These X, Y and Z axes form the XYZ space.

[0046] The position of the origin (X0, Y0, Z0) and the maximum values ​​of the X and Y axes can be set arbitrarily, but in Figure 2, the origin is set at one vertex of the reference area, the maximum value of the X axis is set at the point where the X axis contacts the origin of the reference area and the end of the position opposite on the X axis, and the maximum value of the Y axis is set at the point where the Y axis contacts the origin of the reference area and the end of the position opposite on the Y axis.

[0047] That is, the maximum coordinate of the X axis is set so as to be tangent to the edge line segment of the reference area, and similarly, the maximum coordinate of the Y axis is set so as to be tangent to the edge line segment of the reference area.

[0048] 3A, the maximum value of the X axis is set at the midpoint between the origin of the reference area and the edge of the position opposite on the X axis, and the maximum value of the Y axis is set at the point of contact between the origin of the reference area and the edge of the position opposite on the Y axis. In other words, at any position in the origin reference area, the maximum coordinate of the X axis is set at a position that does not reach the edge line segment of the reference area, and the maximum coordinate of the Y axis is set so as to be tangent to the edge line segment of the reference area.

[0049] 3B, the maximum values ​​of both the X and Y axes are set to intermediate positions up to the edge of the reference area. In other words, the maximum coordinates of the X and Y axes are set at arbitrary positions in the origin reference area so as not to reach the edge line segments of the reference area.

[0050] In either case, the maximum value of the Z axis is set to the surface position of the mounting table 10. In other words, the maximum coordinate of the Z axis is set so as to be in contact with the surface of the mounting table 10.

[0051] As described above, the X, Y, and Z axes are set, and the scales are set by dividing the X, Y, and Z axes at specified intervals. The coordinates of the X, Y, and Z axes are set by the number of scale marks from the origin (X0, Y0, Z0).

[0052] Next, a process for setting the Z coordinate when inserting the welding tool 6 into the lamination interface 18 of the laminated member 9 will be described.

[0053] FIG. 4A is a diagram showing the Z coordinate of the insertion depth of the joining tool 6 into the laminated member 9. As shown in FIG.

[0054] The friction stir welding apparatus 1 inserts the welding tool 6 into the workpieces 9 to a desired position, i.e., to an insertion depth, while rotating the welding tool 6 at a predetermined rotational speed, and advances the welding tool 6 in the welding direction along the welding line. In the present invention, the insertion depth is set as follows.

[0055] The Z coordinate is set so that the welding tool 6 penetrates the second member (member to be welded 9b) arranged on the upper side of the laminated members 9 and the tip of the welding tool 6 is inserted to the drilling depth of the first member (member to be welded 9a) on the lower side of the laminated members 9. The friction stir welding apparatus 1 acquires this value from an input unit (not shown) and stores it in the memory unit of the control unit 11. This position is set as Z1 in Z-axis coordinate, and a welding line is set on the XY plane at this position.

[0056] The drilling depth is set in the test welding stage of the friction stir welding apparatus 1 according to the welding strength required for the application of the formed laminate 19.

[0057] FIG. 4B is a diagram showing the direction in which the joining tool 6 is inserted into the laminated member 9. As shown in FIG.

[0058] When inserting the welding tool 6 into the lamination interface 18 of the laminated members 9, there are two possible methods, as shown in FIG. 4B : inserting it from above the laminated members 9, or inserting it from the side of the laminated members 9. However, inserting the welding tool 6 from the side of the laminated members 9 is difficult because the entrance (the end of the laminated members 9) will be distorted. If the laminated members 9 cannot be accessed from above, friction stir welding is considered difficult in the first place, but if the laminated members 9 are composed of two relatively thick members to be welded 9a, 9b, it is possible to achieve this because distortion is less likely to occur. In either case, it is preferable to insert the welding tool 6 into the laminated members 9 from above.

[0059] Next, the process of setting the joining line will be described.

[0060] FIG. 5 is a diagram showing a joining line 20 set on the XY plane at an insertion depth Z1.

[0061] As described above, the welding line 20 is set on the XY plane where the tip of the welding tool 6 is at the Z coordinate Z1. On the XY plane, the welding line 20 is set by forming a line segment with the (X, Y, Z) coordinates of the friction stir welding starting end 21 and the (X, Y, Z) coordinates of the friction stir welding ending end 22.

[0062] The X coordinate of the friction stir welding starting end 21 and the X coordinate of the friction stir welding finishing end 22, which indicate the length of the weld line 20, and the Y coordinate indicating the number of weld lines 20, are set prior to actual operation of the friction stir welding apparatus 1 according to the diameter of the welding tool 6, the areas of the first member (members to be welded 9a) and the second member (members to be welded 9b), and the welding strength required for the intended use of the formed laminate 19. The friction stir welding apparatus 1 obtains these values ​​from an input unit (not shown) and stores them in the memory unit of the control unit 11.

[0063] For example, when the coordinates indicating the length of the weld line 20 are such that the X coordinate of the friction stir welding starting end 21 is X1 and the X coordinate of the friction stir welding ending end 22 is X2, and the number of weld lines is n, they are set as follows, where the position of each weld line 20 in the Y-axis direction is indicated by Yn.

[0064] 5, when n welding lines 20 are set, the welding lines 20 are (1) a line segment connecting the friction stir welding start end (X1, Y1, Z1) and the friction stir welding end end (X2, Y1, Z1), (2) a line segment connecting the friction stir welding start end (X1, Y2, Z1) and the friction stir welding end end (X2, Y2, Z1), and (3) a line segment connecting the friction stir welding start end (X1, Yn, Z1) and the friction stir welding end end (X2, Yn, Z1). Friction stir welding is performed along these welding lines 20.

[0065] The joining lines 20 are set so as not to overlap each other.

[0066] A more specific process for setting the joining line will be described with reference to FIG.

[0067] As described above, the welding line 20 is set on the XY plane where the tip of the welding tool 6 is at the Z coordinate Z1. On the XY plane, the welding line 20 is set as a collection of line segments connecting first coordinates indicating the (X, Y, Z) coordinates of the friction stir welding starting end 21, second coordinates indicating the (X, Y, Z) coordinates of the friction stir welding ending end 22, and third coordinates indicating the (X, Y, Z) coordinates of the midpoint. The number of the third coordinates is set as an integer equal to or greater than 0.

[0068] These (X, Y, Z) coordinates are set to optimum values ​​by test running the friction stir welding apparatus 1 according to the welding strength required for the application of the laminate 19 to be formed. The friction stir welding apparatus 1 acquires these values ​​from an input unit (not shown) and stores them in the memory unit of the control unit 11.

[0069] First, the case where the joining line 20 is a simple straight line will be described using the left diagram of FIG. 6. In this case, first and second coordinates are set, but it is not necessary to set a third coordinate. When setting multiple joining lines 20, it is sufficient to set the first and second coordinates corresponding to each joining line. For example, in the case of two joining lines, they are set as follows.

[0070] (First coordinate)1-(Second coordinate)1 (First coordinate)2-(Second coordinate)2 In other words, when m1 and m2 are different natural numbers, n1 and n2 are different or the same natural numbers, and the weld line 20 is a straight line, the weld line 20 is set by a line segment formed by connecting a first coordinate (Xm1, Yn1, Z1) indicating the coordinate of the starting end of the friction stir welding and a second coordinate (Xm2, Yn2, Z1) indicating the coordinate of the ending end of the friction stir welding.

[0071] Next, the setting of a triangular joining line 20 will be described using the central diagram in FIG. 6. In this case, it is sufficient to set one each of the first coordinate, second coordinate, and third coordinate. When setting multiple joining lines 20, it is sufficient to set the first coordinate, second coordinate, and third coordinate corresponding to each joining line. For example, in the case of two joining lines, they are set as follows.

[0072] (First coordinate) 1 - (Third coordinate) 1 - (Second coordinate) 1 (First coordinate)2 - (Third coordinate)2 - (Second coordinate)2 Next, the setting of a joining line 20 having a complex shape that is close to a curve (or is a curve) will be described using the right diagram in FIG. 6. In this case, it is sufficient to set one first coordinate and one second coordinate, and multiple third coordinates. When multiple joining lines 20 are set, it is sufficient to set first coordinates, second coordinates, and multiple third coordinates corresponding to each joining line. For example, in the case of two joining lines, they are set as follows.

[0073] (First coordinate) 1 - (Third coordinate) 11 - (Third coordinate) 1n - (Second coordinate) 1 (First coordinate)2 - (Third coordinate)21 - (Third coordinate)2n - (Second coordinate)2 In other words, when l and p are natural numbers, m1 and m2 are different natural numbers, and n1 and n2 are different or the same natural numbers, and the welding line 20 is not a straight line, that is, when the welding line 20 is a line segment consisting of a combination of multiple straight lines or when the welding line 20 is a line segment including a curve, the welding line 20 is set as a collection of line segments formed by connecting first coordinates (Xm1, Yn1, Z1) indicating the coordinates of the starting end of the friction stir welding, second coordinates (Xm2, Yn2, Z1) indicating the coordinates of the ending end of the friction stir welding, and third coordinates p (Xl, Yp, Z1) of an intermediate point set at a midpoint between the coordinates of the starting end of the friction stir welding and the coordinates of the ending end of the friction stir welding.

[0074] Alternatively, the weld line 20 may be set automatically. A trajectory based on a two-dimensional function drawn on the XY plane at the insertion depth Z1 is assumed in advance, and it is determined whether the required weld strength can be ensured for the laminate 19 formed by friction stir welding along the weld line 20 based on this trajectory. If it is confirmed that this can be ensured, the two-dimensional function is stored in the memory of the control unit 11, and friction stir welding is carried out along the trajectory based on this function.

[0075] In any method for setting the joining lines 20, the joining lines 20 are set so that they do not overlap each other.

[0076] As described above, the process of friction stir welding the lamination interface 18 of the laminated member 9 using the friction stir welding apparatus 1 that sets the (X, Y, Z) space, the insertion depth of the welding tool 6, and the welding line 20 will be described.

[0077] FIG. 7 shows a flowchart of the friction stir welding method performed by the friction stir welding apparatus 1 of this embodiment when the lamination interface 18 is one layer.

[0078] First, in step S1, the XYZ space and the coordinates of the friction stir welding start and end points of the desired n welding lines are set. The first to last welding lines are friction stir welded in order.

[0079] The process of the friction stir welding apparatus 1 is as follows.

[0080] (1) Enter the number of joining lines, the X and Y coordinates of each joining line, and the insertion depth.

[0081] (2) An XYZ space is set, and the (X, Y, Z) coordinates of the friction stir welding start end and friction stir welding end end of the welding line are set on the XY plane at the insertion depth Z1.

[0082] Next, in step S2, the parameter k=1 is set.

[0083] Next, in step S3, the tip of the welding tool is inserted into the friction stir welding starting end of the kth welding line, and then in step S4, the welding tool is advanced along the welding line until it reaches the friction stir welding terminal end to perform friction stir welding.

[0084] When the welding tool reaches the end of the friction stir welding, the welding tool is removed from the laminate (step S5).

[0085] Next, in step S6, it is determined whether the condition k = n is satisfied, and if the condition k = n is not satisfied (No), after calculating k = k + 1 (step S7), the process returns to step S3 and repeats the processing from step S3 onwards. On the other hand, if the condition k = n is satisfied (Yes), the processing of friction stir welding of the lamination interface of the laminated members is terminated.

[0086] A process for forming a laminate with a desired number of layers, three or more, will be described with reference to Fig. 8. Fig. 8 is a diagram showing a process for forming a laminate with a desired number of layers.

[0087] As shown in the upper diagram of Figure 8, the lamination interface of a laminated member in which a first member and a second member are stacked is friction stir welded to form the first laminate. Then, as shown in the center diagram of Figure 8, this laminate is used as a new first member, a new second member is placed on top of it to form a new laminated member, and the lamination interface is friction stir welded to form the next laminate. Furthermore, as shown in the lower diagram of Figure 8, this laminate is used as a new first member, a new second member is placed on top of it to form a new laminated member, and the lamination interface is friction stir welded to form the next laminate. By repeating this process, laminates with the desired number of layers are formed.

[0088] In addition, the desired number of laminates can also be formed by preparing a plurality of laminates in advance, each formed by friction stir welding the lamination interfaces of the laminated members of the first member and the second member, stacking these laminates, and friction stir welding the lamination interfaces to form a laminate. [Example]

[0089] Second Embodiment A friction stir welding apparatus and a friction stir welding method according to a second embodiment of the present invention will be described with reference to FIGS. 9A to 9C.

[0090] 9A to 9C are diagrams illustrating a process for forming a three-layer stack. In this example, a variation of the process for forming a stack of three or more layers as desired is described in Example 1 (FIG. 8).

[0091] When forming a laminate 19 having three or more layers, as shown in FIG. 9A, first, a joining line 20 is set in the Y-axis direction for a laminate member consisting of a first member (member to be joined 9a) and a second member (member to be joined 9b), and a first laminate is formed by friction stir welding along the joining line 20. Next, a third member (member to be joined 9c) is placed on the first laminate, and then a joining line 20 is set in the same position (overlapping position) as the first laminate in the XY plane when viewed from above. Then, friction stir welding is performed along the joining line 20 to form a second laminate consisting of the first member (member to be joined 9a), the second member (member to be joined 9b), and the third member (member to be joined 9c).

[0092] In this way, by setting the joining line 20 at the same position in the XY plane when viewed from above for a plurality of members to be joined, it is possible to form a stack 19 with uniform joining quality.

[0093] Depending on the thickness (especially if thin) and area of ​​the workpieces 9a, 9b, and 9c, it is also possible to form a laminated member consisting of three layers of the workpieces 9a, 9b, and 9c, and then friction stir weld the three layers at once to form a laminate.

[0094] Furthermore, as shown in FIG. 9B, it is also possible to shift the position of the joining line 20 in the X-axis direction when forming a second laminate consisting of the first laminate and a third member (member to be joined 9c) relative to the position of the joining line 20 when forming a first laminate consisting of a first member (member to be joined 9a) and a second member (member to be joined 9b).

[0095] As shown in FIG. 9B, by setting the joining lines 20 in a staggered pattern in the XY plane when viewed from above for multiple members to be joined, the joining strength of the stack 19 can be improved when the area of ​​the stacked members (members to be joined) is relatively large.

[0096] 9C, it is also possible to cross the position of the joining line 20 when forming a second laminate consisting of the first laminate and a third member (member to be joined 9c) with the position of the joining line 20 when forming a first laminate consisting of a first member (member to be joined 9a) and a second member (member to be joined 9b). In other words, the joining line 20 is set in the Y-axis direction for the laminated member consisting of the first member (member to be joined 9a) and the second member (member to be joined 9b), and the joining line 20 is set in the X-axis direction for the laminated member consisting of the first laminate and the third member (member to be joined 9c).

[0097] As shown in Figure 9C, by setting the joining line 20 in the XY plane when viewed from above for multiple joined members, the joining strength of the stack 19 can be improved when the area of ​​the stacked members (joined members) is relatively large, as in Figure 9B.

[0098] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0099] 1... friction stir welding apparatus, 2... apparatus main body, 3... Z-axis up-down movement drive mechanism, 4... spindle support, 5... welding tool holder, 6... welding tool, 7... shoulder portion, 8... probe portion (welding pin), 9, 9a, 9b, 9c... workpieces (laminate members), 10... placement table, 11... control unit (control device), 12... X-axis forward / backward drive mechanism, 13... X-axis forward / backward movement drive motor, 14... spindle motor, 15... spindle holder, 16... spindle, 17... Z-axis drive motor, 18... lamination interface, 19... laminate, 20... welding line, 21... friction stir welding starting end, 22... friction stir welding ending end

Claims

1. A friction stir welding apparatus for forming a laminate by friction stir welding a lamination interface of laminated members in which a first member and a second member, each of which is a plate-shaped metal and has a predetermined thickness, are stacked in a thickness direction with the first member arranged on a lower side and the second member arranged on an upper side, a friction stir welding device which sets a virtual XYZ space at a reference height position which indicates a predetermined height position above a mounting table on which the laminated members are placed, and causes a welding tool to rotate at a predetermined rotational speed and advance at a predetermined advancement speed along one or more welding lines which are set by (X, Y, Z) coordinates in the XYZ space, thereby friction stir welding the laminated interface, thereby forming the laminate.

2. The friction stir welding apparatus according to claim 1, where m1 and m2 are different natural numbers, and n1 and n2 are different or the same natural number, and when the welding line is a straight line, the welding line is set by a line segment formed by connecting first coordinates (Xm1, Yn1, Z1) indicating the coordinates of a starting end of the friction stir welding and second coordinates (Xm2, Yn2, Z1) indicating the coordinates of an ending end of the friction stir welding.

3. The friction stir welding apparatus according to claim 1, where l and p are natural numbers, m1 and m2 are different natural numbers, and n1 and n2 are different or the same natural numbers, and in the case where the welding line is a line segment formed by a combination of a plurality of straight lines, or in the case where the welding line is a line segment including a curve, the welding line is set as a collection of line segments formed by connecting first coordinates (Xm1, Yn1, Z1) indicating the coordinates of a starting end of the friction stir welding, second coordinates (Xm2, Yn2, Z1) indicating the coordinates of an end end of the friction stir welding, the coordinates of the starting end of the friction stir welding, and a third coordinate p (Xl, Yp, Z1) of an intermediate point set at a midpoint between the coordinates of the starting end of the friction stir welding and the coordinates of the end end of the friction stir welding.

4. The friction stir welding apparatus according to claim 2, Z1 indicates an insertion depth when the joining tool is inserted into the layup members, and is a value equal to the size when the joining tool penetrates the second member and then is inserted into the first member to a predetermined drilling depth, the first coordinates indicate position coordinates of a tip end of the welding tool at a starting point when the welding tool is advanced on the XY plane in the Z1 direction, The friction stir welding apparatus, wherein the second coordinates indicate position coordinates of a tip of the welding tool at an end point when the welding tool is advanced on the XY plane in Z1.

5. The friction stir welding apparatus according to claim 3, Z1 indicates an insertion depth when the joining tool is inserted into the layup members, and is a value equal to the size when the joining tool penetrates the second member and then is inserted into the first member to a predetermined drilling depth, the first coordinates indicate position coordinates of a tip end of the welding tool at a starting point when the welding tool is advanced on the XY plane in the Z1 direction, the second coordinates indicate position coordinates of a tip end of the welding tool at an end point when the welding tool is advanced on the XY plane in Z1, the third coordinates indicate position coordinates that a tip of the welding tool passes through on an XY plane at Z1 while the welding tool starts to move from the first coordinates to the second coordinates when the welding tool is moved.

6. The friction stir welding apparatus according to claim 4, the Z1, the number of the welding lines, and the first coordinates and the second coordinates corresponding to each of the welding lines are set at a stage prior to actual operation of the friction stir welding apparatus, depending on the materials of the first member and the second member, the thicknesses of the first member and the second member, and the welding strength required for the application of the formed laminate.

7. The friction stir welding apparatus according to claim 5, the Z1, the number of the weld lines and the first coordinates and the second coordinates corresponding to each of the weld lines, and the number of the intermediate points corresponding to each of the weld lines and the third coordinates corresponding to each of the intermediate points are set at a stage prior to actual operation of the friction stir welding apparatus, depending on the materials of the first member and the second member, the thicknesses of the first member and the second member, and the welding strength required for the application of the formed laminate.

8. The friction stir welding apparatus according to claim 7, wherein a tip of the welding tool is inserted into the k-th first coordinate, where k is a natural number, and the welding line formed by the initial first coordinate, the second coordinate, and the third coordinate is friction stir welded, and then the welding tool is removed from the laminated members, and the tip of the welding tool is inserted into the k+1-th first coordinate, and the welding line formed by the next first coordinate, the second coordinate, and the third coordinate is friction stir welded, thereby repeating this process to friction stir weld all of the welding lines and form the laminated body.

9. The friction stir welding apparatus according to claim 1, a friction stir welding apparatus characterized by repeating the process of using the laminate as a new first member, stacking a new second member on top of the new first member to form a new laminate member, and friction stir welding the lamination interface of the new laminate member to form a new laminate, thereby forming a laminate having a desired number of layers.

10. The friction stir welding apparatus according to claim 1, a rectangular area that is a horizontal movable range of the welding tool at the reference height position is set as a reference area; In the reference area, a predetermined position is set as the origin of the XYZ space represented by coordinates (X0, Y0, Z0); A line segment connecting the origin and a predetermined position parallel to one side of the reference area and moving away from the main body of the friction stir welding apparatus is set as an X-axis, A line segment that connects the origin and a predetermined position that is perpendicular to the X axis, parallel to one side of the reference area, and moves away from the origin is set as a Y axis; A line segment that starts from the origin and extends vertically downward to the surface of the mounting table is set as a Z axis; The friction stir welding apparatus is characterized in that the XYZ space is formed by the X axis, the Y axis, and the Z axis.

11. The friction stir welding apparatus according to claim 10, a friction stir welding apparatus, characterized in that scales are set by dividing the X-axis, the Y-axis, and the Z-axis at predetermined intervals, and coordinates of the X-axis, the Y-axis, and the Z-axis are set by the number of scales from the origin.

12. The friction stir welding apparatus according to claim 1, The laminate is used as a first laminate for a new first member, a new second member is stacked on top of the new first member to form a new laminate member, and the lamination interface of the new laminate member is friction stir welded to form a new laminate as a second laminate, a welding line of the first laminate and a welding line of the second laminate are set to overlap each other on an XY plane when viewed from above.

13. A friction stir welding method for forming a laminate by friction stir welding a lamination interface of laminated members that are stacked in a thickness direction by placing a first member and a second member, each of which is a plate-shaped metal and has a predetermined thickness, on a lower side and an upper side, respectively, and forming a laminate, (a) setting a virtual XYZ space at a reference height position indicating a predetermined height position in the upper direction of a mounting table on which the stacked members are placed; (b) setting one or more joining lines defined by (X, Y, Z) coordinates in the XYZ space; (c) forming the laminate by friction stir welding the lamination interfaces by rotating a welding tool at a predetermined rotational speed and advancing the welding tool at a predetermined advancing speed along the welding line; A friction stir welding method comprising:

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